Java Programming - MCQ Practice Questions

What will be the output of the following code? Object lock = new Object(); synchronized(lock) { synchronized(lock) { System.out.println("Nested"); } }

Which interface would you use to submit multiple tasks and wait for all of them to complete?

What is the difference between notify() and notifyAll() in Java?

Which of the following best describes CyclicBarrier?

What happens when a thread acquires a lock on an object and then calls wait()?

In a scenario where Thread A holds Lock1 and waits for Lock2, while Thread B holds Lock2 and waits for Lock1, what is this called?

What is the output of this code? ExecutorService executor = Executors.newSingleThreadExecutor(); executor.submit(() -> System.out.println("Task 1")); executor.submit(() -> System.out.println("Task 2")); executor.shutdown();

Which method is used to forcefully stop a thread in modern Java?

What happens if an exception is thrown inside a synchronized block?

In Java 21 Virtual Threads, what is the key advantage over platform threads?

What does the volatile keyword guarantee in Java multithreading?

What is the output of the following code? volatile int counter = 0; counter++; // in multiple threads Which issue may occur?

What is CyclicBarrier used for in multithreading?

Which of the following is true about CountDownLatch?

What is the purpose of the wait() method in Java?

In a synchronized block, if notifyAll() is called, what happens?

What is the primary difference between Semaphore and Mutex?

What happens when Thread.interrupt() is called on a thread?

In a deadlock scenario, which of the following is always true?

What is the key difference between Callable and Runnable?